Trends in Fluid Therapy

(cid:639) Crystalloid has been recognized as a safe solution that can be liberally administered. Recently, this liberal policy has been reevaluated because the postoperative weight gain due to large accumulation of fluid is strongly linked to postoperative complications. Optimization of the blood volume (BV), which is one of the targets of fl uid therapy, has not been evaluated in clinical settings. Bedside monitoring of BV was developed as part of the construction of rational fl uid therapy. Plasma dilution of certain doses of dye can be used to estimate BV. Bedside monitoring of BV was developed by applying the theory of pulse spectrophotometry to the estimation of plasma dye concentration non-invasively. Pulse oximetry is a well-developed clinical monitoring method based on the theory of pulse spectrophotometry. The author developed a bedside monitor, the (cid:108) DDG-analyzer (cid:122) , with the pulse spectrophotometry team at Nihon Kohden Co., Ltd. This monitoring method has elucidated how fl uid therapy is an effi cient method of expanding BV in surgical patients. Numerous clinical experiments using this monitor has gradually revealed that conventional fl uid therapy using crystalloid is not as effi cient as expected. This suggests that crystalloid should not be used as much due to considerable weight gain as a result of the administered fl uid accumulating mainly in the interstitial space rather than in the intravascular space. Recent British guidelines for fl uid therapy for surgical patients (British Consensus Guidelines on Intravenous Fluid Therapy for Adult Surgical Patients (GIFTASUP) ) also supports this concept, and recommends reducing crystalloid administration. In the next era, colloid could be used preferentially to reduce complications, and replace massive crystalloid infusions.